1. Field of the Invention
The present invention relates to a soft magnetic alloy powder, a compact, and an inductance element.
2. Related Background Art
Conventionally, a powder magnetic core is generally used as a type of magnetic core provided in an inductance element or the like. An Fe-based soft magnetic metal powder being a soft magnetic material is often used as a material of this powder magnetic core. Since the material of the Fe-based soft magnetic metal powder itself has low electric resistance, core loss becomes relatively high even if insulation between particles is enhanced. In recent years, according to the demand for downsizing of the inductance element or the like, it is to be desired that the electric resistance of the powder magnetic core is increased to decrease the core loss. For this reason, a further improvement is demanded for the conventional soft magnetic materials as described above. A technique of adding Si (silicon) in the metal powder was proposed in order to increase the electric resistance of the Fe-based soft magnetic metal powder. However, the addition of Si increases the hardness of the Fe-based soft magnetic metal powder, and thus moldability thereof becomes insufficient for the powder magnetic core and unsuitable for practical use.
Fe—Ni-based soft magnetic alloy (so-called permalloy alloy) powders are often adopted as materials of the powder magnetic core other than the Fe-based soft magnetic metal powder. However, reduction of core loss at high frequencies is insufficient in the Fe—Ni-based soft magnetic alloy powders. Then means of adding Si, Ge, or Sn being the Group 14 element was proposed for the purpose of reducing the core loss of the Fe—Ni-based soft magnetic alloy powders (cf. Patent Document 1). According to Patent Document 1, the electric resistance of the material itself increases when a predetermined amount of the Group 14 element such as Si is added in the Fe—Ni-based soft magnetic alloy powder.
Another example of addition of Si in the permalloy alloy likewise is the one disclosed in Patent Document 2. According to Patent Document 2, influence of oxygen on magnetic characteristics can be reduced by adding Si as a deoxidizing component. However, Patent Document 2 describes that Si should be limited to not more than 1 wt % because excessive addition of Si is harmful to the soft magnetic property. This Patent Document 2 also describes that Co may be added in the permalloy alloy in order to enhance the magnetic flux density or the like.
Patent Document 3 discloses use of Cr, Si, Cu, and Co as additive elements in the PC permalloy alloy, but describes nothing about an additive amount thereof.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-23811    [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-173745    [Patent Document 3] Japanese Patent Application Laid-Open No. 63-114108